Hippocampal functional connectivity after whiplash injury is linked to the development of chronic pain

Brain-centric theories propose that chronic pain is driven and maintained by maladaptive negative emotional learning, with the hippocampus playing a crucial role in the transition from acute to chronic pain. However, little is known about what triggers this maladaptive learning in the first place, especially in the early acute stages following injury. We imaged 110 patients within days of whiplash and mild traumatic brain injury and tested whether hippocampal adaptations impart risk for chronic pain one year later. Patients who went on to develop chronic pain one year later showed increased connectivity between the hippocampus and its posterior network, as well as increased network connectivity across posterior hippocampal network nodes and the amygdala bilaterally. This connectivity was linked to anxiety and increased with time lapse from injury to brain scans. Our findings link rapid hippocampal network reorganization with the development of chronic pain. In this study, the authors used imaging to identify increased hippocampal, posterior hippocampal, and amygdala connectivity in people who had experienced whiplash and mild traumatic brain injury and who developed chronic pain one year later.